A Review on Biological Control of Fungal Plant Pathogens Using Microbial Antagonists
ABSTRACT The objective of this study was to review the published research works on biological control of fungal plant diseases during past 50 years. Fungal plant pathogens are among the most important factors that cause serious losses to agricultural products every year. Biological control of plant diseases including fungal pathogens has been considered a viable alternative method to chemical control. In plant pathology, the term biocontrol applies to the use of microbial antagonists to suppress diseases. Throughout their lifecycle, plants and pathogens interact with a wide variety of organisms. These interactions can significantly affect plant health in various ways. Different mode of actions of biocontrol-active microorganisms in controlling fungal plant diseases include hyperparasitism, predation, antibiosis, cross protection, competition for site and nutrient and induced resistance. Successful application of biological control strategies requires more knowledge-intensive management. Various methods for application of biocontrol agents include: application directly to the infection court at a high population level to swamp the pathogen, application at one place in which biocontrol microorganisms are applied at one place (each crop year) but at lower populations which then multiply and spread to other plant parts and give protection against pathogens and one time or occasional application that maintain pathogen populations below threshold levels. Commercial use and application of biological disease control have been slow mainly due to their variable performances under different environmental conditions in the field. To overcome this problem and in order to take the biocontrol technology to the field and improve the commercialization of biocontrol, it is important to develop new formulations of biocontrol microorganisms with higher degree of stability and survival. Majority of biocontrol products are applied against seed borne and soil borne fungal pathogens, including the causal agents of seed rot, damping-off and root rot diseases. These products are mostly used as seed treatment and have been effective in protecting several major crops such as wheat, rice, corn, sugar beet and cotton against fungal pathogens. However, in some cases, biocontrol microorganisms have also been tested as spray application on foliar diseases, including powdery mildew, downy mildew, blights and leaf spots. A few post harvest fungal diseases have also been controlled by the use of antagonistic fungi and bacteria. Biocontrol microorganisms are also being used as the form of composts in some plants. Research data and observations in nurseries have shown that addition of composted organic matter to potting mixes results in suppression of soil borne diseases. A significant improvement have been made in different aspects of biological control of fungal plant diseases, but this area still need much more development and investigations to solve the existing problems. In order to have more effective biological control strategies in the future, it is critical to carry out more research studies on some less developed aspects of biocontrol, including development of novel formulations, understanding the impact of environmental factors on biocontrol agents, mass production of biocontrol microorganisms and the use of biotechnology and nano-technology in improvement of biocontrol mechanisms and strategies. Future outlooks of biocontrol of plant diseases is bright and promising and with the growing demand for biocontrol products among the growers, it is possible to use the biological control as an effective strategy to manage plant diseases, increase yield, protect the environment and biological resources and approach a sustainable agricultural system.
Full-textDOI: · Available from: Mohammad Pessarakli, Oct 16, 2014
- SourceAvailable from: Carmen Romeralo Tapia
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- "These microbial antagonists are known as biological control agents (BCAs). The interaction of a BCA and a pathogen include: (i) mycoparasitism, the pathogen is directly attacked by a BCA that kills it or its propagules; (ii) antibiosis and metabolite production, i.e., the BCAs produce substances that are toxic to the pathogen; (iii) competition for nutrients, i.e., the BCAs occupy the same ecological niche of the pathogen and therefore deplete the nutrients necessary for its establishment ; (iv) induction of the plant defence system, i.e., the stimulation of the host plant defences by the presence of the BCAs; and (v) the barrier effect, caused by the presence of mycorrhizal fungi (Schoeman et al. 1999; Alabouvette et al. 2006; Ownley and Windham 2007; Heydari and Pessarakli 2010; Diez and Alves- Santos 2011). Among the potential BCAs there are several fungal endophytes, i.e., fungi that live inside the plant tissue and maintain either a neutral, detrimental or beneficial relationship with the host plant (Sieber 2007; Backman and Sikora 2008). "
ABSTRACT: Biological control agents (BCAs), and among them some species of fungal endophytes, are potential substitutes for chemical pesticides in the control of plant diseases due to their non-toxicity to human beings and their surrounding environment. One mode of action of fungal BCAs is through their bioactive, extracellular products, which can inhibit the growth of pathogens. In this study, the effect of fungal filtrates from four endophyte isolates (Trichoderma viride, Aureobasidium pullulans, Aureobasidium sp. and the unknown endophyte 20.1) on the advance of the pathogen Gremmeniella abietina on 2-year Pinus halepensis seedlings was evaluated. Both preventive and therapeutic treatments of the filtrates were studied by applying the filtrates either before or after the pathogen inoculation, respectively. Since G. abietina is a necrotrophic fungus, the length of the necrosis produced by the pathogen was used as response variable in our experiment. In order to explore the chemical composition of the fungal filtrates, a simple HPLC screening of UV-absorbing components was conducted. The results of the study showed that all fungal filtrates were able to reduce the advance of G. abietina when compared to the control seedlings, regardless of the time of inoculation and the treatment. Low-molecular weight phenolic compounds could be detected in some but not all filtrates, warranting further studies on the possible role of these compounds in fungal filtrates.European Journal of Plant Pathology 08/2015; DOI:10.1007/s10658-015-0719-3 · 1.49 Impact Factor
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- "Published data on this area remain sparse perhaps because they may involve industry secret in comparison with the considerable volume of literature describing selection procedure, mechanism of action or genetics of biological control agents. One approach to overcome inconsistent performance by biological control agent is through integration of multiple microbes into individual biological control formulations (Asghar and Pessarakli, 2010), and a second approach is through diversified the application method (Zhang et al., 2010). With regards to Collectotrichum gloeosporioides on black pepper, application of microbial biological control agent may improve disease suppression as these pathogens can infect the host near the soil line and in the foliar canopy. "
ABSTRACT: Anthracnose caused by Collectotrichum gloeosporioides is a serious disease of black pepper. The antagonistic effect of three Bacillus species, i.e. Bacillus strain CBF, YCA0098 and YCA5593, were tested against Collectotrichum gloeosporioides in vitro and in vivo. In vitro test showed that all Bacillus species significantly reduce the mycelia growth and spore germination of the C. gloeosporioides. Scanning electron microscopy revealed significant inhibition of C. gloeosporioides spore germination on pepper leaves surface. Combination of bacterial strain CBF, YCA0098 and YCA5593 maintained but not increased the inhibitory effect on spore germination of C. gloeosporioides when cells were co-incubated with C. gloeosporioides and when the pathogen was incubated in mixture of cell-free culture extracts. Combination of strains maintained efficacy in control of C. gloeosporioides in pepper vines compared to individual strains, but reduced variability and improved consistency between experiments, especially mixture of strain CBF, YCA0098 and YCA5593.
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- "Previously, different microbial species such as Bacillus spp., Pseudomonas spp., Trichoderma spp., Streptomyces spp. and nonpathogenic Fusarium spp., have been effectively used for the control of soil-borne plant pathogens (Heydaria and Pessarakli, 2010; Raza et al., 2013). Among those, Streptomycetes strains have their own importance. "
ABSTRACT: A rhizobacterium with broad spectrum antifungal activity was isolated from the rhizosphere of a healthy cucumber plant in a Fusarium wilt diseased field. Phylogenetic tree analysis based on similarity percentage showed that the bacterium was 99% affiliated with the species Streptomyces goshikiensis. The strain, coded as Streptomyces goshikiensis YCXU, inhibited in vitro a broad range of phytopathogenic fungi, so it was selected for more detailed characterization. The strain could utilize different carbon sources and exhibited catalase, β-1,3-glucanase, chitinase and urease enzyme activities. The strain showed maximum growth at the pH of 7, temperature of 28°C and NaCl concentration of 1%. The stain was able to produce antifungal diffusible and volatile organic compounds that significantly inhibited the growth of pathogenic fungi. In the greenhouse experiments, watermelon plants fresh and dry weights were significantly increased, and the incidence of Fusarium wilt was decreased by 67% when the strain enriched by a bioorganic fertilizer was applied to both nursery soil and pot soil (NS). The treatment NS also showed 88.9% less pathogen population in soil as compared to control. The use of biocontrol agents decreased the stress indicator enzymes and malondialdehyde content by 55-70% and 62%, respectively as compared to control. The denaturing gradient gel electrophoresis (DGGE) analysis showed significant variations in the fungal and bacterial community structures of all treatments resulted from UPGMA cluster analysis. This study showed that Streptomyces goshikiensis YCXU could be a potential biocontrol agent for controlling watermelon Fusarium wilt disease.Biological Control 11/2014; 81. DOI:10.1016/j.biocontrol.2014.11.012 · 1.64 Impact Factor